Guards at Custóias prison in Porto district on Wednesday had to fire rubber bullets into the air to restore order after more than half the inmates refused to eat lunch.

The president of the National Union of the Prison Guard Corps (SNCGP), Jorge Alves, said that inmates are back in their locked cells, having not eaten.

According to Alves, inmates of A, B and C wings of the prison, when called for lunch, refused to go to the cafeteria and started throwing items from their cells at the prison guards and causing a disturbance.

The union president said that prison bosses ordered that shots be fired into the air restore order, by which means guards managed to get inmates back into the cells.

A source at the Directorate-General for Parole and Prison Services (DGRSP) told Lusa that there was no riot, just that a substantial part of the inmates did not want to eat. The same source said that there were no disturbances, nor any need for intervention.

Another prison guard source told Lusa that the situation was resolved by staff who were on duty at the time, but that a special intervention unit was poised to move in if necessary.

Alves also told Lusa that he was unaware of the reason why the inmates refused to have lunch.

The reported disturbances at Custóias, which has more than 1,000 inmates, took place less than 24 hours after inmates in one wing of Lisbon prison rioted, shouting, burning mattresses and paper, and smashing some items, forcing guards to "use force”. The situation was brought under control on Tuesday night and on Wednesday, according to Alves; the inmates are back in their cells, having only left them to lunch in groups.